Connector-plug part for an optical plug-in connection

ABSTRACT

In order to advantageously weld a pre-mounted connector-plug part ( 1 ) to an optical waveguide cable, the connector-plug part is provided with a pin holder ( 4 ) receiving a connector-plug pin ( 2 ) on a pin receiving section ( 5 ). Preferably, two cladding parts ( 8, 8 ′) form a cable receiving section ( 6 ) in said pin holder. In order to carry out welding in a simple manner on the bare end ( 22 ) of the end of a fiber, the cladding parts ( 8, 8 ′) can be pivoted around a hinge ( 9, 9 ′) between an open position and a closed position. A dividable protective sheath ( 25, 25 ′) is provided inside the cable receiving section or inside the cladding parts and can enclose the weld. When mounted, the protective sheath can be decoupled from the cladding parts ( 8, 8 ′).

The invention relates to a connector-plug part for an optical plug-inconnection according to the precharacterizing clause of claim 1. Suchconnector-plug parts are pre-assembled at the factory, the connection tothe actual optical waveguide cable taking place directly at theconnector-plug part by welding under conditions in the field. Thepre-assembly is intended to allow the difficult centering and fixing ofthe optical waveguide in the connector-plug pin to be carried out undermore suitable factory conditions.

Connector-plug parts of a comparable generic type have been disclosedfor example by WO 96/31795 or by EP 864 888. For attaching the weldingelectrodes, special openings or clearances are provided. A disadvantageof the known connector-plug parts is that the welded location itself isdifficult to access and that observation of the welding operation isalso made more difficult. Furthermore, the bare optical waveguide in thedirect region of the welded location is only insufficiently protectedand safeguarded against tensile forces. It is therefore an object of theinvention to provide a connector-plug part of the type stated at thebeginning with the aid of which the welding operation at the fiber stubcan be carried out as unhindered as possible and with good viewingconditions. It is intended in this case that both the pre-assembly andthe final assembly of the connector-plug part can be carried out quicklyand without complex auxiliary means. Finally, the welded location isalso to be optimally protected against mechanical loading and againstsoiling after final assembly.

This object is achieved according to the invention by a connector-plugpart which has the features in claim 1. The connector-plug pin itselfmay in this case be pre-assembled independently of its mounting orstructure in the pin receiving section. The cladding part, which can bepivoted at the joint, makes it possible in a particularly simple way forthe welded location at the fiber stub to be exposed and consequentlymade accessible. The protective sleeve which can be divided and closedaround the welded location ensures optimal protection of the weldedlocation after closing of the cladding part into the closed position.

The pin holder advantageously comprises two shell parts, which can befitted together along the longitudinal center axis, each shell parthaving a pivotable cladding part, and the protective sleeve likewisecomprising two sleeve shells, each of which can be fastened on theinside of a cladding part. In this way, the sleeve shells of theprotective sleeve can also be closed by the closing movement of the twocladding parts, it likewise being possible for the prior fastening onthe inside of the cladding parts to take place already at the factory.In certain cases, however, it would also be conceivable to connect thetwo sleeve shells to each other by a hinge extending in the longitudinaldirection. Furthermore, the protective sleeve does not necessarily haveto be fastened to the cladding part in advance.

The pivotable cladding parts may altogether form the cable receivingsection and be connected to the pin receiving section at the joint.Alternatively, however, it would also be conceivable for the pivotablecladding part to extend only over part of the length of the cablereceiving section.

Particular advantages arise in technical production terms if the pinholder comprises two identical shell parts which can be fitted togetheron a plane running through the longitudinal center axis. In this way,different types of shell parts do not have to be produced, because thepin holder can be assembled from two identical shell parts.

In certain cases it would also be conceivable for at least the cablereceiving section to comprise two, preferably identical, shell partswhich can be fitted together along the longitudinal center axis, eachshell part forming the pivotable cladding part which is connected to thepin receiving section at the joint, and the protective sleeve likewisecomprising two sleeve shells, each of which can be fastened on theinside of a cladding part. In such a case, the entire pin holder couldbe formed in one piece, the connector-plug pin being molded for exampleinto the pin receiving section. The cladding parts are molded in onepiece onto the pin receiving section in such a way that they can beclosed during the assembly of the cable receiving section.

For the connection of neighboring shell parts, projections andclearances which engage in one another, in particular conical lugs andlug openings, may be provided on their contacting surfaces. Depending onthe conicity chosen, the two shell parts may be joined together byslight pressure. Depending on the arrangement of the lugs and lugopenings, such a snap connection also permits snapping together inspecific sequences.

In order to avoid stresses at the welded location, it is expedient ifthe protective sleeve is mounted displaceably in the axial direction inthe cable receiving section in relation to the latter. In this way,compensation is provided even for movements which are initiated byforces on the connector-plug pin.

Optimal mounting of the welded location on the optical waveguide isobtained if the two sleeve shells of the protective sleeve have on theirinside, facing the optical waveguide, a channel which receives theoptical waveguide and is provided with an adhesive material. The channelmay for example be coated with silicone material, which encloses theoptical waveguide.

Alternatively, however, it is also possible for an adhesive which bringsabout a fixed connection in the closed state to be applied to theoptical waveguide already before the closing of the two sleeve shells.

The two sleeve shells of the protective sleeve may also have on theirinside, facing the optical waveguide, a receiving section at each oftheir two ends, which respectively clasps the circumferential surface ofan optical waveguide cable and of the optical waveguide stub in aclamping manner. In this way, the protective sleeve acts as a tensionrelieving means for the bare welded location, in that tensile forces aretransmitted from the circumferential surface of the optical waveguidecable to the circumferential surface of the optical waveguide stub.

Further advantages in final assembly can be achieved if the two sleeveshells of the protective sleeve are elastically deformable and if theycan be fixed on the inside of the cladding parts in such a way thattheir insides, facing the optical waveguide, run in a concavely curvedmanner and that the sleeve shells can be fitted together in the closedposition of the cladding parts by pressure from the outside. The concavecurvature in the pre-assembled state has the effect that, during theassembly, the abovementioned receiving sections first clasp thecircumferential surface of the optical waveguide cable or of the opticalwaveguide stub, thereby avoiding loading of the welded location.

In a way similar to the cladding parts, the sleeve shells may have ontheir contacting surfaces interengaging projections and clearances, inparticular lugs and lug openings, which are arranged in such a way thatthey still do not engage in one another in the concave state of thesleeve shells. Consequently, a non-positive connection only takes placeduring pressing together from the outside.

This function is improved still further by each sleeve shell beingfastened by an insertion head in a corresponding opening in the claddingpart, the insertion heads being releasable from the openings after thepressing together of the sleeve shells for axial release of theprotective sleeve. The fixing at the insertion heads is consequentlyonly temporary and serves for captively fastening the sleeve shells onthe cladding parts until final assembly.

After the release of the insertion heads from the openings, theprotective sleeve can be displaced in the axial direction. A safeguardagainst twisting is thereby achieved particularly advantageously byarranging on the inside of the cladding parts a slot which adjoins theopening and extends in the axial direction and in which the insertionheads are displaceable after the axial release of the protective sleeve.

The pin holder and the protective sleeve advantageously consist ofplastic material, the joint being a film hinge. However, it would alsobe quite conceivable to produce the pin holder in particular from metal,while the joint could be a mechanical snap joint.

The connector-plug part according to the invention makes it possible ina particularly simple way to mount the connector-plug pin with limiteddisplaceability in the pin receiving section under axial springprestressing. As a result, not only final assembly, but alsopre-assembly is simplified and relatively simply formed connector-plugpins of a particularly hard material, such as ceramic or hard metal, canbe used.

Further individual features and advantages of the invention emerge fromthe exemplary embodiment described below and from the drawings, inwhich:

FIG. 1 shows a perspective exploded drawing of a connector-plug partaccording to the invention,

FIG. 2 shows the connector-plug part according to FIG. 1 in thepre-assembled state,

FIG. 3 shows a cross section through the pre-assembled connector-plugpart according to FIG. 2,

FIG. 4 shows a cross section through the connector-plug part accordingto FIG. 3 after the welding operation and shortly before the closing ofthe cladding parts,

FIG. 5 shows the connector-plug part according to FIG. 4 shortly beforethe final closing of the cladding parts,

FIG. 6 shows the connector-plug part according to FIG. 5 with thecladding parts fully closed but the sleeve shells still open,

FIG. 7 shows the connector-plug part according to FIG. 6 during theclosing of the sleeve shells,

FIG. 8 shows the connector-plug part according to FIG. 7 with axiallydecoupled protective sleeve and

FIG. 9 shows a perspective representation of a ready assembledconnector-plug part shortly before insertion into a connector-plughousing.

As represented in FIG. 1, a connector-plug part, designated as a wholeby 1, substantially comprises a pin holder, designated as a whole by 4,and a connector-plug pin 2 of a generally very hard material, such asceramic or hard metal for example. The pin holder itself in turncomprises two shell parts 10, 10′, which can be fitted together on aplane running through a longitudinal center axis 3. Finally, the pinholder 4 (in the closed state) is divided into a pin receiving section 5and a cable receiving section 6.

The two shell parts 10, 10′ consist for example of plastic material,preferably being injection-molded in the opened-out position fortechnical molding-related reasons. The two shell parts are completelyidentical. For the connection to each other, conical lugs 12 andcorresponding lug openings 13 are provided on the mutually contactingsurfaces 11. The hermaphroditic arrangement of these connecting meansallows the sleeve-like pin holder 4 to be produced from shell parts of asingle type.

In the case of the present exemplary embodiment, each shell part 10, 10′forms over the entire length of the cable receiving section 6 a claddingpart 8, 8′, which is connected to the pin receiving section 5 by a filmhinge 9. The cladding parts can in this case be swung outunproblematically by about 90° with respect to the longitudinal centeraxis 3.

The connector-plug pin 2 is provided on its outer circumferentialsurface with two plane-parallel clearances 18. A pair of correspondingribs 17 on the inside of the pin receiving section engage in theseclearances, a certain resilient displacement in the direction of thelongitudinal center axis 3 being allowed. A helical compression spring19 provides the necessary axial prestressing. An optical waveguide stub21 has already been fixedly connected to the connector-plug pin 2, andcentered in it. This stub has a bare, stripped end 22.

The perspective representation of detail a shows the cladding part 8 ina position in which it has been turned somewhat further. It is evidentfrom this that the cladding part is provided with a through-opening 44.This opening is adjoined on the inside by a slot 45, which extends inthe axial direction. The cladding part 8′ is formed as a mirror image.In the perspective representation of detail b, the cladding part 8 hasbeen turned by 180°. From this perspective, the positioning means 36,which later serve for the radial positioning of the connector-plug partin a connector-plug housing, can also be seen.

Arranged on the inside of each of the two cladding parts 8, 8′ is asleeve shell 25, 25′. The representation of detail c shows the sleeveshell 25 turned by 180°. The two sleeve shells together produce aprotective sleeve. At each of both ends, such a protective sleeve has areceiving section 39 and 39′, half of which can respectively be seen inFIG. 1. Arranged on the inside of this receiving section are teeth 40,which dig into the coating of an optical waveguide during the closing ofthe two sleeve shells. Also arranged on the inside 38 of the sleeveshells are lugs 41 and lug openings 42, to be precise not on the outsidebut in the region of the center. A channel 37, which is coated forexample with a silicone material, extends in the axial direction. Thischannel later receives the bare optical waveguide with the weldedlocation. The silicone material could also be substituted by an adhesivelayer, which however has been applied to the optical waveguide inadvance.

For the temporary fixing to the two cladding parts 8, 8′, respectivelyprovided on the outside of the sleeve shells is an insertion head 43,which is dimensioned in such a way that it is fixed with a wringing fitin the corresponding opening 44.

FIGS. 2 and 3 show the connector-plug part as a pre-assembled unit 20,in which the connector-plug pin 2 is captively and axially resilientlyenclosed in the pin receiving section 5. The sleeve shells 25 and 25′have been inserted into the respective cladding parts 8 and 8′ and arelikewise captively held there. As can be seen in particular from FIG. 3,the two sleeve shells are deformed somewhat by the insertion of theinsertion heads 43 into the openings 44, so that they are convexlycurved. The receiving sections 39, 39′ are in this case supported on theinside of the cladding parts 8, 8′.

In this pre-assembled state, the bare end 22 of the optical waveguidestub 21 is then welded onto the end 23 of an optical waveguide cable 7in a way known per se under conditions in the field (FIG. 4). As isevident, the welding operation is not in this case hindered in any wayby the pivoted-open cladding parts.

In FIG. 4, the welded location 24 between the bare optical waveguideends 22 and 23 is symbolically represented. After the welding operation,the two cladding parts 8, 8′ are swung together, in that force isexerted from the outside in the direction of the arrow K1. This closingmovement is continued according to FIG. 5 until the lugs 12 engage inthe lug openings 13. As represented, in this state the welded opticalwaveguide cable is not yet influenced by forces.

The final closing of the two cladding parts 8, 8′ takes place accordingto FIG. 6 by force acting in the direction of the arrow K2 on both endsof the cladding parts. The receiving sections 39, 39′ therebyrespectively grasp the coating of the optical waveguide cable 7 and ofthe optical waveguide stub 21 with non-positive engagement. However, thetwo sleeve shells 25, 25′ are not yet connected to each other in thecentral region of the welded location 24, because the lugs 41 do not yetengage in the lug openings 42 as a result of the convex curvature.

Only now is force exerted on the center of the sleeve shells 25, 25′,according to FIG. 7, from the outside in the direction of the arrow K3.As this happens, on the one hand the lugs 41 force themselves into thelug openings 42 and on the other hand the insertion heads 43 arereleased from the openings 44, so that the protective sleeve as a wholeis decoupled in the axial direction.

As can be seen from FIG. 8, the protective sleeve 25, 25′ can now bedisplaced back in the axial direction, the insertion heads 43 moving inthe slot 45 and in this way ensuring a safeguard against twisting. Theone-sided arrangement of the slot 45 proceeding from the opening 44 hasthe effect, however, that the displacement is only possible toward thecable side 7.

Also generally required for the handling of the optical plug-inconnection is a connector-plug housing 14, as represented in FIG. 9.This provides the anchorage in the socket part and the protection of theend face of the connector-plug pin 2. In the case of the exemplaryembodiment, the pin holder 4 has a conical section 15, which can bepressed into a conical receptacle 16 on the connector-plug part. Theangular positioning takes place in this case at the positioning means36. The optical waveguide cable is fixedly connected to the pin holder 4by means of a crimping sleeve 34.

1. A connector-plug part (1) for an optical plug-in connection, with aconnector-plug pin (2), in which an optical waveguide stub (21)extending over a longitudinal center axis (3) is held, and with asleeve-like pin holder (4) with a pin receiving section (5), in whichthe connector-plug pin is held, and with a cable receiving section (6),to which the end of an optical waveguide cable (7) can be fixed in atension-resistant manner, it being possible for the optical waveguidestub to be welded to the optical waveguide end (23) on the cable side,characterized in that the cable receiving section (6) has at least onecladding part (8, 8′), which can be pivoted at a joint (9) by a certainpivoting angle between an open position and a closed position, the end(22) of the optical waveguide stub (21) that is to be welded lying inthe pivoting region of the cladding part, and in that a protectivesleeve (25, 25′) which can be divided and closed around the weldedlocation is arranged within the cable receiving section (6).
 2. Theconnector-plug part as claimed in claim 1, characterized in that the pinholder (4) comprises two shell parts (10, 10′), which can be fittedtogether along the longitudinal center axis (3), each shell part havinga pivotable cladding part (8, 8′), and the protective sleeve likewisecomprising two sleeve shells (25, 25′), each of which can be fastened onthe inside of a cladding part.
 3. The connector-plug part as claimed inclaim 2, characterized in that the two cladding parts (8, 8′) altogetherform the cable receiving section (6) and are connected to the pinreceiving section (5) at the joint (9).
 4. The connector-plug part asclaimed in claim 2, characterized in that the pin holder (4) comprisestwo identical shell parts (10, 10′), which can be fitted together on aplane running through the longitudinal center axis (3).
 5. Theconnector-plug part as claimed in claim 1, characterized in that atleast the cable receiving section (6) comprises two preferably identicalshell parts, which can be fitted together along the longitudinal centeraxis (3), each shell part forming the pivotable cladding part (8, 8′),which is connected to the pin receiving section (5) at the joint (9),and the protective sleeve likewise comprising two sleeve shells (25,25′), each of which can be fastened on the inside of the cladding part.6. The connector-plug part as claimed in claim 2, characterized in thatneighboring shell parts (10, 10′) have on their contacting surfaces (11)projections and clearances which engage in one another, in particularlugs (12) and lug openings (13).
 7. The connector-plug part as claimedin claim 2, characterized in that the protective sleeve (25, 25′) ismounted displaceably in the axial direction in the cable receivingsection (6) in relation to the latter.
 8. The connector-plug part asclaimed in claim 2, characterized in that the two sleeve shells (25,25′) of the protective sleeve have on their inside (38), facing theoptical waveguide, a channel (37) which receives the optical waveguideand is provided with an adhesive material.
 9. The connector-plug part asclaimed in claim 2, characterized in that the two sleeve shells (25,25′) of the protective sleeve have on their inside (38), facing theoptical waveguide, a receiving section (39, 39′) at each of their twoends, which respectively clasps the circumferential surface of anoptical waveguide cable and of the optical waveguide stub in a clampingmanner.
 10. The connector-plug part as claimed in claim 2, characterizedin that the two sleeve shells (25, 25′) of the protective sleeve areelastically deformable and in that they can be fixed on the inside ofthe cladding parts (8, 8′) in such a way that their insides (38), facingthe optical waveguide, run in a concavely curved manner and that thesleeve shells can be fitted together in the closed position of thecladding parts by pressure from the outside.
 11. The connector-plug partas claimed in claim 10, characterized in that the sleeve shells (25,25′) have on their contacting surfaces (38) interengaging projectionsand clearances, in particular lugs (41) and lug openings (42), which arearranged in such a way that they still do not engage in one another inthe concavely curved state of the sleeve shells.
 12. The connector-plugpart as claimed in claim 10, characterized in that each sleeve shell(25, 25′) is fastened by an insertion head (43) in a correspondingopening (44) in the cladding part, the insertion heads being releasablefrom the openings after the pressing together of the sleeve shells foraxial release of the protective sleeve.
 13. The connector-plug part asclaimed in claim 12, characterized in that a slot (45) which adjoins theopening (44) and extends in the axial direction is arranged on theinside of the cladding parts (8, 8′) and in that the insertion heads(43) are displaceable in the slot after the axial release of theprotective sleeve as a safeguard against twisting.
 14. Theconnector-plug part as claimed in claim 1, characterized in that the pinholder and the protective sleeve consist of plastic material and in thatthe joint is a film hinge.
 15. The connector-plug part as claimed inclaim 1, characterized in that the connector-plug pin (2) is mountedwith limited displaceability in the pin receiving section (5) underaxial spring prestressing.